package main

import (
	. "fmt"
	"math"
)


func main() {
	r:= Rectangle{10,20}
	Println(r.area())
	c:=Circle{3}
	Println(c.area())
}

type Rectangle struct {
	width, height float64
}

type Circle struct {
	radius float64
}

func (c Circle) area() float64 {
	return c.radius * c.radius * math.Pi
}

func (c Rectangle) area() float64 {
	return c.width * c.height
}
